Hi Tic,
We travel a lot with our kids, and when they were infants, we found the PeaPod travel bed worked out the best for us. It is so lightweight and folds up really compact, unlike the bulkier pack n play cribs, and I love that it can also be used on the beach for nap time. It has a mesh material on the sides which protects the baby from bugs and will keep a crawling baby safely confined at night. You can find them pretty cheap on Ebay or Craigslist if you don't mind getting a used one.
Here is a link to see what one looks like:
http://www.onestepahead.com/catalog/...oductId=536932
I would also make sure to pack enough baby sunblock, a sun hat, and some powdered Pedialyte to keep baby well hydrated. I also always pack some infant/child tylenol and benadryl just in case. And, of course you already know about the other baby necessities like diapers, wipes, bottles, pacis, etc.